JPH08328265A - Formation of fine patterns - Google Patents

Abstract

PURPOSE: To make it possible to prevent pattern inclination by selectively forming oxidized metallic films or silylated films on a resist surface and dry etching the resist with these selectively formed films as mask. CONSTITUTION: The surface of a semiconductor silicon substrate 105 is spin- coated with a resist 104 to form a resist film. Next, the patterns on the mask 102 are exposed by using an KrF excimer laser 101 to generate an acid. The surfaces of the exposed parts of the resist are changed to have hydrophilicity by such generation of the acid, and left as it is thereby, steam 106 is a adsorbed on the exposed part surface of the resist and water is diffused. Further, the vapor 108 of methyl triethoxysilane is sprayed for three minutes to the resist surface to selectively form the oxidized films 109. Next, the resist is heated to evaporate the generated alcohol and the unreacted water and to cure the selectively formed oxidized films 111 to form the mask. The resist is etched by using O2 RIE112 to form the patterns.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fine pattern forming method for manufacturing semiconductor devices and integrated circuits.

[0002]

2. Description of the Related Art Conventionally, in the manufacture of ICs and LSIs, pattern formation is performed by photolithography using ultraviolet rays. With the miniaturization of elements, the use of short-wavelength light sources has been promoted, and it is now possible to form a resist pattern with a minimum of 0.25 micron or less by a deep ultraviolet ray exposure method using a chemically amplified resist. However, as the aspect ratio of the resist pattern becomes higher with the miniaturization, a new problem occurs in the conventional wet development method.

FIG. 9 shows a sectional view of a conventional resist pattern forming process by wet development. In FIG. 9, a resist 304 is applied on a semiconductor substrate 305 (see FIG.
(A)) A mask 302 having a desired pattern is transferred onto a semiconductor substrate by a reduction projection exposure machine using far ultraviolet rays as exposure light (FIG. 9 (b)). Next, the resist is dipped in a developing solution 902 such as an alkaline aqueous solution, and a resist pattern is formed by using the difference in dissolution rate between the exposed area and the unexposed area (FIG. 9C). Then, the developing solution and the resist dissolved in the developing solution are washed away with a rinse solution 903 of pure water, and finally spin-dried by rotating at high speed (FIG. 9D).
(E)).

As described above, when the fine pattern is formed by using the conventional wet development method, the aspect ratio of the resist pattern becomes high, so that the adjacent pattern as shown in FIG. There is a problem in that the resist pattern leans against and the pattern collapses.

Therefore, surface-resolving resists which carry out dry development without wet development using a developing solution after exposure have been actively studied. A typical silylation method as a surface-resolution resist is to coat a resist on a semiconductor substrate, expose the resist to radiation, and heat the resist to bring it into contact with a silylating agent such as HMDS in a liquid or vapor phase. To selectively form a silylated layer on the resist surface. Then, using the silylated layer as a mask, the resist is treated with O ₂ RI.
Etch with E. In the silylation method, the photosensitizer in the exposed area is chemically changed to indenecarboxylic acid. On the other hand, since the polymer in the unexposed area is cross-linked with the photosensitizer by the heat treatment after the exposure, the silylation treatment such as HMDS gives selectivity to the diffusion of SI in the exposed area and the unexposed area, and the silylated layer is formed in the exposed area. It is selectively formed. The resist is etched by O ₂ RIE using the silylated layer as a mask to form a negative pattern.

[0006]

However, in the conventional surface-resolving resist using silylation, the SI of the unexposed portion is insufficient because the crosslinking of the polymer in the unexposed portion and the photosensitizer in the heat treatment after exposure is not sufficient. Diffuses on the resist surface. Therefore, there is a problem in that the selectivity between the exposed portion and the unexposed portion in O2RIE is poor and a residue is generated in the unexposed portion. Further, as the exposure wavelength is shortened, the absorption of the resist is increased, so that there is a problem that the silylation contrast between the exposed portion and the unexposed portion in the resist is lowered and the resolution is lowered. Furthermore, when a silylated resist is used,
There is a problem that the silylated resist after the steps such as dry etching cannot be removed by the conventional cleaning.

[0007]

The present invention has been devised to overcome such a problem, and a resist containing a polymethacrylic acid derivative as a main polymer which produces an acid upon exposure to radiation on a semiconductor substrate. A step of applying, a step of exposing the resist to radiation, a step of absorbing water in a region where the acid of the resist is generated, and water vapor and a metal alkoxide vapor are brought into contact with the resist surface to the exposed portion of the resist. A resist pattern is formed by a step of selectively forming a metal oxide film and a step of etching the resist using the metal oxide film as a mask. Further, the present invention comprises the steps of applying a resist having a polyvinylphenol derivative as a main resin which generates an acid upon exposure to radiation onto a semiconductor substrate, exposing the resist to radiation, and generating acid in the resist. A step of absorbing water in a region, a step of bringing water vapor and a metal alkoxide vapor into contact with the resist surface to selectively form a metal oxide film on an exposed portion of the resist, and etching the resist using the metal oxide film as a mask A resist pattern including the steps described above is formed.

A surface resolution resist having an absorption coefficient of 1 / μm or less for the exposure wavelength of the resist applied to the semiconductor substrate in the present invention is used.

Further, in the present invention, a step of applying an organic polymer on a semiconductor substrate, a step of applying a resist sensitive to radiation on the organic polymer, a step of exposing the resist to radiation, and the generation of acid in the resist. A step of absorbing water in the region, a step of contacting water vapor and a metal alkoxide vapor to the resist surface to selectively form a metal oxide film on the exposed portion of the resist, and the metal oxide film as a mask to form the resist. A resist pattern is formed by etching.

Further, according to the present invention, a step of applying a resist that generates an acid by radiation onto a semiconductor substrate, a step of exposing and transferring a mask pattern onto the resist with a first radiation, and a step of exposing the semiconductor substrate to a second radiation. Step of irradiating the entire surface with water, a step of absorbing water in the acid-generated region of the resist, and a step of contacting water vapor and metal alkoxide vapor to the resist surface to selectively form a metal oxide film on the exposed portion of the resist A resist pattern is formed by etching the resist using the metal oxide film as a mask.

Further, according to the present invention, a step of applying a resist which generates an acid by radiation onto a semiconductor substrate, a step of exposing and transferring a mask pattern onto the resist by a first radiation, and a step of heat-treating the semiconductor substrate. A step of absorbing water in a region where the acid of the resist is generated, a step of bringing a water vapor and a metal alkoxide vapor into contact with the resist surface to selectively form a metal oxide film on an exposed portion of the resist, and the metal oxide film. A resist pattern is formed by etching the resist using the mask as a mask.

Further, according to the present invention, a step of applying an organic polymer on a semiconductor substrate, a step of applying a resist on the organic polymer on the semiconductor substrate, a step of exposing the resist to radiation, and a heat treatment of the resist. A step of contacting a silylating agent in a liquid phase or a gas phase to selectively form a silylated layer on the resist, and etching the resist using the silylated layer as a mask to form a fine pattern. .

Further, according to the present invention, a step of applying a resist on a semiconductor substrate, a step of exposing and transferring a mask pattern of the resist with a first radiation, and a front irradiation of the semiconductor substrate with a second exposure wavelength, A step of heat-treating the resist; a step of selectively contacting a silylating agent in a liquid phase or a gas phase to form a silylated layer on the resist; and etching the resist using the silylated layer as a mask. Form a fine pattern.

[0014]

In the present invention, a metal oxide film or a silylated layer is selectively formed on the resist surface, and dry etching is performed using the selectively generated film as a mask, so that pattern collapse does not occur and a fine pattern with a high aspect ratio can be obtained with high accuracy. A resist pattern can be formed. Furthermore, when a silylated resist is used, it becomes easy to remove the silylated resist after a process such as dry etching.

[0015]

【Example】

(Embodiment 1) First, a fine pattern forming method according to a first embodiment of the present invention will be described below.

FIG. 1 is a sectional view showing the steps of a fine pattern forming method according to the first embodiment of the present invention. The resist is a polymethacrylic acid derivative as shown below 1,
A copolymer of 2,3,4-tetrahydronaphthylideneimino p-styrene sulfonate (NISS) and methyl methacrylate (MMA) was used.

[0017]

Embedded image

First, a resist 104 is spin-coated on a semiconductor silicon substrate 105, heated at 90 ° C. for 60 seconds to form a resist film having a thickness of 1.2 μm, and then the mask 102.
The upper pattern is exposed by using the KrF excimer laser 101, and NISS is decomposed on the surface of the exposed portion of the resist to generate an acid (FIG. 1A). At this time, the exposed surface of the resist becomes hydrophilic due to the generation of acid.
Next, the semiconductor substrate is exposed to air with a relative humidity of 95% at 30 ° C.
By leaving it for a minute, water vapor 106 is adsorbed on the surface of the resist exposed portion and the depth of 50 nm
Water was diffused up to (Fig. 1 (b)). Further, while maintaining a relative humidity of 95% at 30 ° C., vapor 108 of methyltriethoxysilane (MTEOS) was sprayed onto the resist surface for 3 minutes to selectively form an oxide film 109 on the resist exposed portion surface (FIG. 1 ( c)). At this time, an acid serves as a catalyst to form an oxide film by the reaction shown below, and at the same time, alcohol is also produced.

[0019]

Embedded image

Next, by heating the resist at 90 ° C. for 60 seconds, the generated alcohol and unreacted water are volatilized to cure the selectively formed oxide film 111 (FIG. 1).
(D)). O ₂ RIE1 using the cured oxide film as a mask
12 was used to etch the resist to form a pattern (FIG. 1E). The O ₂ RIE conditions were a parallel plate type RIE, a power of 900 W, a pressure of 0.7 Pa, and a flow rate of 40 SCCM.

Further, by using the fine pattern forming method described above, a KrF excimer laser stepper with NA 0.42 was exposed using a Levenson type phase shift mask,
A 2 μm line and space pattern was formed. The pattern shape at that time is shown in FIG. Resist film thickness is 1.
A pattern having a high aspect ratio of 2 μm and an aspect ratio of 6 or more could be formed. Then, using this resist pattern as a mask, the polysilicon film or oxide film deposited on the semiconductor substrate is transferred by dry etching. At this time, if a resist having an alicyclic organic group (eg, adamantyl group) in a polymethacrylic acid derivative is used as the resist used in the first embodiment, dry etching resistance can be improved.

[0022]

[Chemical 4]

In the examples of the present invention, 1,2,3,4-tetrahydronaphthylideneimino p-styrene sulfonate (NISS) was used as the acid generating group in the resist, but an acid generating sulfonic acid as the acid generating group was used. If it is a generator, the exposed surface of the resist becomes hydrophilic due to the generation of an acid on the exposed surface, and the semiconductor substrate is allowed to stand in air at 30 ° C. and 95% relative humidity for 20 minutes.
Water vapor is adsorbed on the surface of the resist exposed portion, and water diffuses from the surface of the resist exposed portion to a depth of 50 nm. While maintaining a relative humidity of 95% at 30 ° C., a vapor of methyltriethoxysilane (MTEOS) is blown onto the resist surface for 3 minutes to selectively form an oxide film 309 on the exposed surface of the resist.

In the embodiment of the present invention, KrF excimer exposure light was used as the exposure wavelength.
A fine pattern can be similarly formed by using rF excimer light. At this time, in order to sufficiently adsorb water vapor on the resist exposed portion surface and selectively generate the oxide film 109 having high dry etching resistance on the resist exposed portion surface, the resist absorption coefficient for ArF excimer light is 1 / μm or less. Is preferred.

This is because when the transmittance is low, the acid generated by irradiation is localized only on the resist surface portion, so that the amount of water vapor adsorbed is small and the resist resists etching when exposed to a methyltriethoxysilane atmosphere. This is because a high oxide film does not grow. As a specific example, when diazodisulfonic acid shown below is used as the acid generator of the resist, it does not have a benzene ring structure.
Since there is no light absorption in nm, the absorption coefficient of the resist for ArF excimer light can be set to 1 / μm or less.

[0026]

Embedded image

In the embodiment of the present invention, the resist is 1,2,3,4-tetrahydronaphthylideneimino p-.
Although a copolymer of styrene sulfonate (NISS) and methyl methacrylate (MMA) was used, a resist prepared by blending polymethyl methacrylate and a sulfonic acid generator can also be used.

As described above, in this embodiment, since the resist contains the methyl methacrylate derivative and the acid generator, pattern collapse does not occur and the selectivity in dry etching can be improved. .

(Embodiment 2) Next, a fine pattern forming method according to a second embodiment of the present invention will be described. From a radiation-sensitive material containing a polymer compound in which all or part of the phenolic hydroxyl group on the semiconductor substrate is substituted with a protective group that is easily removed by the action of an acid, or a monomolecular compound and an acid generator Resist is dropped and 1.0μ
Spin coating is performed to form a resist film having a thickness of m, and baking is performed on a hot plate at 90 ° C. for 1 minute. Specific examples of the polymer compound in which all or part of the above-mentioned phenolic hydroxyl group is substituted with a protective group that is easily removed by the action of an acid include, for example, poly (p-tert-butoxycarbonyloxystyrene) and poly ( p-tert-butoxystyrene), poly (p-tetrahydropyranyloxystyrene), poly (p- (1-ethoxyethoxy) styrene),
Poly (p- (1-methoxy-1-methylethoxy) styrene), poly (p-trimethylsilyloxystyrene), poly (p-tert-butoxycarbonyloxystyrene-p-hydroxystyrene), poly (p-tert-butoxystyrene-p -Hydroxystyrene), poly (p-tetrahydropyranyloxystyrene-p-hydroxystyrene), poly (p- (1-ethoxyethoxy) styrene-p-hydroxystyrene), poly (p- (1-methoxy-1-methylethoxy)) Styrene-p-hydroxystyrene), poly (p-trimethylsilyloxystyrene-p-hydroxystyrene), poly (p-tert-butoxycarbonylmethoxystyrene-p-hydroxystyrene) and the like, but are not limited thereto. Not something. Further, specific examples of the monomolecular compound in which all of the above-mentioned phenolic hydroxyl groups are substituted with a protective group that is easily removed by the action of an acid include, for example, 2,2-bis (4-tetrahydropyranyloxyphenyl) propane, 2 , 2-bis (4-tert-butoxyphenyl) propane, 2,
2-bis (4-tert-butoxycarbonyloxyphenyl) propane, 2,2-bis (4- (1-ethoxyethoxy) phenyl)
Propane, 3,4-dihydro-4- (2,4-di (1-tetrahydropyranyloxy) phenyl-7- (1-tetrahydropyranyloxy) -2,2,4-trimethyl-2H-1-benzopyran, 3,4-
Dihydro-4- (2,4-di (1-tert-butoxy) phenyl-7-
(1-tert-Butoxy) -2,2,4-trimethyl-2H-1-benzopyran, 3,4-dihydro-4- (2,4-di (1-ethoxyethoxy) phenyl-7- (1-ethoxyethoxy) ) -2,2,4-Trimethyl-2H-1-1-benzopyran and the like, but not limited thereto.

After exposure with an excimer stepper having an exposure wavelength of 248 nm and NA: 0.42, 100 ° C. with a hot plate,
It was baked for 1 minute. The mask pattern is exposed using a KrF excimer laser as in the first embodiment,
Acid is generated on the exposed surface of the resist. This time,
The surface of the exposed portion of the resist became hydrophilic due to the generation of acid. By leaving the semiconductor substrate in air at a relative humidity of 95% at 30 ° C. for 20 minutes, water vapor is adsorbed on the surface of the resist exposed portion and the depth of the resist exposed portion becomes 50
Water diffused to nm. While maintaining a relative humidity of 95% at 30 ° C., vapor of methyltriethoxysilane (MTEOS) was blown onto the resist surface for 3 minutes to selectively form an oxide film on the resist exposed portion surface. Resist at 90 ° C 6
By heating for 0 seconds, the generated alcohol and unreacted water were volatilized, and the selectively formed oxide film was cured. Using the cured oxide film as a mask, the resist was etched using O ₂ RIE to form a pattern. Using this resist pattern as a mask, the polysilicon film or oxide film deposited on the semiconductor substrate is transferred by dry etching. Since the polyvinylphenol derivative has high dry etching resistance, the resist pattern could be transferred onto the film on the substrate with high accuracy.

In the embodiment of the present invention, KrF excimer light is used as the exposure wavelength, but ArF having a shorter wavelength as the exposure wavelength is used.
A fine pattern can be similarly formed by using excimer light. At this time, in order to sufficiently adsorb water vapor on the resist exposed portion surface and selectively generate the oxide film 309 having high dry etching resistance on the resist exposed portion surface, the resist absorption coefficient for ArF excimer light is 1 / μm or less. Is preferred. When the transmittance is low, the acid generated by radiation irradiation is localized only on the resist surface, so the amount of water vapor adsorbed is small, and when the resist is exposed to a methyltriethoxysilane atmosphere, an oxide film with high etching resistance is formed. This is because it will not grow.

(Third Embodiment) Next, a third embodiment will be described with reference to FIG. A resist 304 was spin-coated on the semiconductor silicon substrate 305 and heated at 90 ° C. for 60 seconds to form a resist film having a film thickness of 1.2 μm. The resist is a polyvinylphenol derivative PBO shown below.
A chemically amplified resist made of CST (p-tert-butoxycarbonyloxystyrene) was used.

[0033]

[Chemical 6]

Next, the pattern on the mask 302 was exposed using an ArF excimer laser 301. After the exposure, heating on a hot plate at 100 ° C. for 90 seconds removes the t-Boc group from the polyvinylphenol derivative as shown in (Chemical Formula 6) to generate post (p-hydroxystyrene). When treated with a silylating agent such as hexamethyldisilazane, the hydroxyl groups of PHOST are silylated and trimethyl ether is formed on the exposed surface portion. After the silylation layer was selectively formed, the resist was etched using O ₂ RIE310 using the selectively formed silylation layer as a mask to form a pattern. O ₂ RIE conditions are parallel plate type RIE, power 900W, pressure 0.7P.
The flow rate of a and O ₂ was 40 SCCM.

Ar of the resist used in the examples of the present invention
Since the absorption coefficient of the resist for F excimer light is 1 / μm or less, light penetrates to a depth of about 0.1 μm from the resist surface, so that the reduction in silylation contrast is small and a pattern with good resolution after dry etching is obtained. It is formed.

Although hexamethyldisilazane was used as the silylating agent in this example, other silylating agents such as bis (dimethylamino) dimethylsilane may be used instead of hexamethyldisilazane. RIE using O ₂ plasma was used for the dry development method.
CR etching or the like may be used. ArF as the exposure light source
Although the excimer laser is used, a KrF excimer laser or X-ray may be used.

(Embodiment 4) Next, a fourth embodiment will be specifically described with reference to FIG. An organic polymer 400 containing a novolac resin as a main component is applied onto the semiconductor substrate 405 for 1 micron or more and heated at 200 ° C. for 120 seconds. 1,2,3,4-which is a polymethacrylic acid derivative on an organic polymer
A resist 404 made of a copolymer of tetrahydronaphthylideneimino p-styrenesulfonate (NISS) and methyl methacrylate (MMA) was applied to a thickness of 0.2 μm. The pattern on the mask 302 was exposed using a KrF excimer laser 401, and NISS was decomposed on the surface of the exposed portion of the resist to generate an acid. At this time, the surface of the exposed portion of the resist became hydrophilic due to the generation of acid. The semiconductor substrate is placed in air with a relative humidity of 95% at 30 ° C.
By leaving for a minute, water vapor was adsorbed on the surface of the resist exposed portion, and water was diffused from the surface of the resist exposed portion to a depth of 50 nm (FIG. 4 (c)). Methyltriethoxysilane (MTEO) was maintained at 30 ° C and 95% relative humidity.
S) vapor was blown onto the resist surface for 3 minutes to selectively form an oxide film 409 on the resist exposed portion surface (FIG. 4).
(D)). By heating the resist at 90 ° C. for 60 seconds, the generated alcohol and unreacted water were volatilized, and the selectively formed oxide film was cured. Using the cured oxide film as a mask, the resist was etched using O ₂ RIE 412 to form a pattern (FIG. 4F). In the present embodiment, since the multilayer structure is used, the depth of the CVD oxide film is controlled to be thin, the resolution is improved, and the resist can be easily removed in a later step such as dry etching of the film to be etched.

(Fifth Embodiment) Next, a fifth embodiment of the present invention will be described with reference to FIG. Semiconductor silicon substrate 50
5 was spin-coated with a resist 504 and heated at 90 ° C. for 60 seconds to form a resist film having a thickness of 1.2 μm. A resist composed of a polyvinylphenol derivative and an acid generator was applied as the resist. After the pattern on the mask 502 was exposed and transferred onto the resist by ArF excimer light, the semiconductor substrate was entirely irradiated with KrF excimer light.
At this time, the resist surface exposed by ArF excimer light was crosslinked, but by irradiating the entire surface with KrF excimer light, acid was generated in the unexposed area by ArF excimer light, and the resist surface became hydrophilic. By leaving the semiconductor substrate in air at a relative humidity of 95% at 30 ° C. for 20 minutes, water vapor was adsorbed on the surface of the resist exposed portion and water was diffused from the surface of the resist exposed portion to a depth of 50 nm (FIG. 5 (c)). .
While maintaining a relative humidity of 95% at 30 ° C, vapor of methyltriethoxysilane (MTEOS) is applied to the resist surface 3 times.
After spraying for minutes, an oxide film was selectively formed on the surface of the resist exposed portion (FIG. 5D). By heating the resist at 90 ° C. for 60 seconds, the generated alcohol and unreacted water were volatilized, and the selectively formed oxide film was cured. Using the cured oxide film as a mask, the resist was etched using O ₂ RIE511 to form a pattern (FIG. 5).
(E)). In this embodiment, Kr is exposed in the unexposed area of the ArF excimer.
By irradiating the entire surface with F excimer light, a CVD oxide film is deposited on the ArF unexposed portion, so that the dry etching resistance of the oxide film is improved and a pattern with good resolution is formed.

(Sixth Embodiment) Next, a sixth embodiment of the present invention will be described with reference to FIG. Semiconductor silicon substrate 60
5 was spin-coated with a resist 604 and heated at 90 ° C. for 60 seconds to form a resist film having a thickness of 1.2 μm. A resist composed of a polyvinylphenol derivative and an acid generator was applied as the resist. The pattern on the mask 602 is exposed and transferred onto the resist by ArF excimer light 601 and then the semiconductor substrate is heated to 110 ° 9 ° C.
Heat treatment was performed for 0 seconds. At this time, the resist surface exposed with ArF excimer light was crosslinked, but by heat treatment with a hot plate, acid was generated in the unexposed portion with ArF excimer light, and the resist surface became hydrophilic. By leaving the semiconductor substrate in air at a relative humidity of 95% at 30 ° C. for 20 minutes, water vapor is adsorbed on the surface of the resist exposed portion and water diffuses from the surface of the resist exposed portion to a depth of 50 nm (FIG. 6 (c)). . While maintaining a relative humidity of 95% at 30 ° C., a vapor of methyltriethoxysilane (MTEOS) was blown onto the resist surface for 3 minutes to selectively form an oxide film 309 on the resist exposed surface (FIG. 6C). ). By heating the resist at 90 ° C. for 60 seconds, the generated alcohol and unreacted water were volatilized, and the selectively formed oxide film was cured. O ₂ with the hardened oxide film as a mask
The resist was etched using RIE312 to form a pattern (FIG. 6D). The O ₂ RIE conditions are parallel plate type RIE, power 900 W, pressure 0.7.
Pa and the flow rate were 40 SCCM. In this example, ArF
Since the CVD oxide film is deposited on the ArF unexposed portion by performing the entire heat treatment on the hot plate after the excimer unexposing, the dry etching resistance of the oxide film is improved by the dry annealing of the oxide film, and a pattern with good resolution is obtained. Is formed.

(Embodiment 7) Next, a pattern forming method in a seventh embodiment will be described with reference to FIG. An organic polymer 702 containing a novolac resin as a main component is applied on a semiconductor substrate 703 by 1.0 micron and baked at 200 ° C. for 120 seconds. Resist 701 on organic polymer 701
Is spin coated and heated at 90 ° C. for 60 seconds to give a film thickness of 0.2
A μm resist film was formed. The resist is ArF.
A chemically amplified resist containing a polyvinylphenol derivative having an absorption coefficient for excimer light of 1 / μm or less as a base polymer was used. Ar the pattern on the mask 705
Exposure was performed using F excimer laser 704 to crosslink the exposed surface of the resist (FIG. 7B). After exposure, heating on a hot plate at 100 ° C. for 90 seconds and treatment with a silylating agent such as hexamethyldisilazane silylates the hydroxyl groups of PHOST and produces trimethyl ether on the exposed surface. At this time, the lower novolak resin is crosslinked and is not silylated. After the silylated layer is selectively formed, the selectively formed silylated layer is used as a mask for O ₂ R
The resist was etched using IE312 to form a pattern (FIG. 7E). O ₂ RIE conditions are parallel plate type RIE, power 900W, pressure 0.7P.
The flow rate of a and O ₂ was 40 SCCM. In the present embodiment, since the multilayer structure is used, the depth of the CVD oxide film is controlled to be thin, the resolution is improved, and the resist can be easily removed in a post-process such as dry etching of the film to be etched.

In this embodiment, novolac resin is used as the lower organic polymer, but polymethacrylate or crosslinked polyvinylphenol may be used as the non-silylated organic polymer. Although hexamethyldisilazane was used as the silylating agent, other silylating agents such as bis (dimethylamino) dimethylsilane may be used instead of hexamethyldisilazane. RIE using O ₂ plasma was used for the dry development method.
CR etching or the like may be used. ArF as the exposure light source
Although the excimer laser is used, a KrF excimer laser or X-ray may be used.

(Embodiment 8) Next, an eighth embodiment will be described with reference to FIG. A resist 804 was spin-coated on a semiconductor silicon substrate 805 and heated at 90 ° C. for 60 seconds to form a chemically amplified resist film having a polyvinylphenol derivative as a base polymer and having a film thickness of 1.2 μm. Mask 8
The pattern on 02 was exposed using ArF excimer laser 801 to crosslink the surface of the exposed portion of the resist (FIG. 8).
(A)). After the entire surface of the semiconductor substrate was irradiated with KrF excimer light, the resist was heated on a hot plate at 100 degrees for 90 seconds. When treated with a silylating agent such as hexamethyldisilazane, the hydroxyl groups of PHOST are silylated and trimethyl ether is formed on the exposed surface portion. After the silylation layer was selectively formed, the resist was etched using O ₂ RIE 812 using the selectively formed silylation layer as a mask to form a pattern (FIG. 8E). As for O ₂ RIE, a parallel plate type RIE is used and a power of 900 is used.
The pressure was W, the pressure was 0.7 Pa, and the flow rate of O ₂ was 40 SCCM. In this embodiment, the unexposed portion of the ArF excimer is entirely irradiated with KrF excimer light to form a silylated film in the unexposed portion of the ArF, so that the dry etching resistance of the silylated film is improved and a pattern with good resolution is obtained. Is formed.

Although hexamethyldisilazane was used as the silylating agent in this example, other silylating agents such as bis (dimethylamino) dimethylsilane may be used instead of hexamethyldisilazane. RIE using O ₂ plasma was used for the dry development method.
CR etching or the like may be used. ArF as the exposure light source
Although the excimer laser is used, a KrF excimer laser or X-ray may be used.

[0044]

As described above, according to the present invention,
Even if the pattern becomes finer and the aspect ratio becomes higher, it is possible to easily and highly accurately form a fine resist pattern without pattern dripping after wet development and dry development. Can greatly contribute to

[Brief description of drawings]

FIG. 1 is a process sectional view of a fine pattern forming method in a first embodiment of the present invention.

FIG. 2 is a sectional view of a fine pattern according to the first embodiment of the present invention.

FIG. 3 is a process cross-sectional view of a fine pattern forming method in a third embodiment of the present invention.

FIG. 4 is a process sectional view of a fine pattern forming method according to a fourth embodiment of the present invention.

FIG. 5 is a process sectional view of a fine pattern forming method in a fifth embodiment of the present invention.

FIG. 6 is a process sectional view of a fine pattern forming method in a sixth embodiment of the present invention.

FIG. 7 is a process sectional view of a fine pattern forming method in a seventh embodiment of the present invention.

FIG. 8 is a process sectional view of a fine pattern forming method in an eighth embodiment of the present invention.

FIG. 9 is a diagram showing a resist pattern shape when a conventional wet development method is used.

FIG. 10 is a process cross-sectional view of a conventional fine pattern forming process for a surface resolution resist.

[Explanation of symbols]

301 KrF excimer laser 302 Mask 303 Acid generation region 304 Resist 305 Semiconductor silicon substrate 306 Water vapor 307 Water vapor absorption region 308 Water vapor and alkoxysilane vapor 309 Oxide film 310 Volatile 311 Oxide film cure 312 O ₂ RIE 401 High aspect ratio resist pattern 501 Amine generation Area 502 Water vapor absorption area 601 Water 602 Alkoxysilane solution 701 Resin film 702 Transmittance increasing area 801 Crosslinking portion 802 Silylation solution 803 Silylation layer 804 Far ultraviolet ray 805 Silylation layer curing 901 Exposure light 902 Developer 903 Rinsing solution

Claims (14)

[Claims] 1. A step of applying a resist which is exposed to radiation to generate an acid on a semiconductor substrate, a step of exposing the resist to radiation, and a step of absorbing water in an acid-generated region of the resist. A fine pattern including a step of contacting water vapor and a metal alkoxide vapor with the resist surface to selectively form a metal oxide film on an exposed portion of the resist, and a step of etching the resist using the metal oxide film as a mask A method of forming a fine pattern, wherein the resist applied on the semiconductor substrate has a methyl methacrylate derivative and an acid generator. 2. The fine pattern forming method according to claim 1, wherein the resist coated on the semiconductor substrate is composed of a copolymer of methyl methacrylate and an acid generating group. 3. The method for forming a fine pattern according to claim 1, wherein the methyl methacrylate derivative has an alicyclic organic group. 4. The method for forming a fine pattern according to claim 1, wherein the resist coated on the semiconductor substrate has an acid generating group which is exposed to radiation to generate a sulfonic acid. 5. The method for forming a fine pattern according to claim 1, wherein the resist coated on the semiconductor substrate is composed of a diazodisulfone compound shown below. Embedded image 6. A step of applying a resist, which is exposed to radiation, to generate an acid on a semiconductor substrate, a step of exposing the resist to radiation, and a step of absorbing water in an acid-generated area of the resist. A fine pattern including a step of contacting water vapor and a metal alkoxide vapor with the resist surface to selectively form a metal oxide film on an exposed portion of the resist, and a step of etching the resist using the metal oxide film as a mask A method of forming a fine pattern, wherein the resist applied on the semiconductor substrate has a polyvinylphenol derivative and an acid generator. 7. The method for forming a fine pattern according to claim 1, wherein the resist applied to the semiconductor substrate has an absorption coefficient of 1 / μm or less with respect to the exposure wavelength. 8. A step of applying a resist on a semiconductor substrate, a step of exposing the resist to radiation, a step of heat-treating the resist, and a step of contacting a silylating agent in a liquid phase or a gas phase to form the resist. A method of forming a fine pattern, comprising: a step of selectively forming a silylated layer on a substrate, and a step of etching the resist using the silylated layer as a mask, the absorption coefficient of the resist applied to the semiconductor substrate with respect to an exposure wavelength. Is 1 / μm or less, a fine pattern forming method. 9. A step of applying an organic polymer on a semiconductor substrate, a step of applying a resist which is exposed to radiation to generate an acid on the organic polymer, a step of exposing the resist to radiation, and a step of applying the resist. A step of absorbing water in the region where the acid is generated, a step of bringing water vapor and a metal alkoxide vapor into contact with the resist surface to selectively form a metal oxide film on the exposed portion of the resist, and using the metal oxide film as a mask And a step of etching the resist to form a fine pattern. 10. The method for forming a fine pattern according to claim 9, wherein the organic polymer coated on the semiconductor substrate is hydrophobic. 11. A step of applying a resist that generates an acid by radiation onto a semiconductor substrate, a step of exposing and transferring a mask pattern onto the resist by a first radiation, and a whole surface of the semiconductor substrate with a second radiation. A step of irradiating, a step of absorbing water in the acid-generated region of the resist, and a step of contacting water vapor and a metal alkoxide vapor to the resist surface to selectively form a metal oxide film on an exposed portion of the resist, And a step of etching the resist using the metal oxide film as a mask. 12. A step of applying a resist which generates an acid by radiation onto a semiconductor substrate, a step of exposing and transferring a mask pattern onto the resist by a first radiation, a step of heat treating the semiconductor substrate, A step of absorbing water in a region where an acid of the resist is generated, a step of contacting water vapor and a metal alkoxide vapor to the resist surface to selectively form a metal oxide film on an exposed portion of the resist,
And a step of etching the resist using the metal oxide film as a mask. 13. A step of applying a non-silylated organic polymer onto a semiconductor substrate, a step of applying a resist onto the organic polymer, a step of exposing the resist to radiation, and a step of heat-treating the resist. A fine pattern forming method comprising: a step of selectively forming a silylated layer on the resist by bringing a silylating agent into contact with the liquid phase or a gas phase; and a step of etching the resist using the silylated layer as a mask. 14. A step of applying a resist on a semiconductor substrate, a step of exposing and transferring a mask pattern of the resist with a first radiation, and a step of irradiating the semiconductor substrate with a second exposure wavelength over the entire surface to heat the resist. A fine process including a step of treating, a step of selectively forming a silylated layer on the resist by contacting a silylating agent in a liquid phase or a gas phase, and a step of etching the resist using the silylated layer as a mask. Pattern formation method.